Clearing mechanism for calculating machines



Nov. 6, 1962 E. K. GRIIP 3,062,444

CLEARING MECHANISM FOR CALCULATING MACHINES Filed Jan. 8, 1960 5 Sheets-Sheet l Arm/swam Nov. 6, 1962 E. K. GRIP 3,062,444 CLEARING MECHANISM FOR CALCULATING MACHINES Filed Jan. 8, 1960 5 Sheets-Sheet 2 Nov. 6, 1962 E. K. GRIP 3,062,444

CLEARING MECHANISM FOR CALCULATING MACHINES Filed Jan. 8, 1960 5 Sheets-Sheet 5 Nov; 6, 1962 E. K. GRIP 3,062,444

CLEARING MECHANISM FOR CALCULATING MACHINES Filed Jan. 8, 1960 s Sheets-Sheet 4 E. K. GRIP CLEARING MECHANISM FOR CALCULATING MACHINES Nov. 6, 1962 5 She Filed Jan. 8, 1960 llWEA/Tflk 56K KONAAD am Irma/5r:

ited fates atent Office 3,062,444 Patented Nov. 6, 1962 3,062,444 CLEARING MECHANISM FOR CALCULATING MACHINES Erik Konrad Grip, Atvidaberg, Sweden, assignor to Aktiebolag Atvidaberg-Facit, Atvidaberg, Sweden, a jointstock company of Sweden Filed Jan. 8, 1960, Ser. No. 1,208 Claims priority, application Sweden Jan. 9, 1959 6 Claims. (Cl. 235144) This invention relates to clearing (zeroizing) mechanisms in calculating machines, particularly those of the pin-Wheel type.

In a known embodiment of such mechanism a toothed clearing rod is disposed in a longitudinal groove in the number or calculating wheel shaft, and the clearing of the wheels is effected by displacing the clearing rod longitudinally of the shaft to make its teeth engage corresponding teeth or notches in the respective wheels, and rotating the shaft and clearing rod to turn the Wheels to zero position. Such mechanism is disclosed, for instance, in German patent specification No. 939,295, issued on Feb. 16, 1956.

In this and other known mechanism of a similar type the shaft and the clearing rod have to start their common rotation from the very beginning of the clearing operation. The teeth on the clearing rod which are destined to engage the number or calculating wheels will be obliged to follow a helical path towards the corresponding projections in the wheels. This may cause difficulties when the digit 9 has been set up in a wheel to be cleared, as the engagement between the clearing rod and the wheel will often become effective before the axial displacement of the clearing rod has been finished. Wear of parts such as the clearing rod teeth will ensue by that reason, and in some cases it might even occur that the engagement between the clearing rod and a wheel will fail completely, and consequently the wheel will not be turned to zero position.

Further, in known mechanism the clearing rod and the shaft effect a complete revolution on clearing, and subsequently the clearing rod (or the shaft) must be forced by spring means abruptly back to its original position. It has proved difficult, by that arrangement, to align the number wheels perfectly in the zero position without having to make manufacturing tolerances uncomfortably small with resulting increased investments and costs.

The normal division of the number wheel peripheries into ten equal digits to 9) will have as a consequence that the rotation angle for the helical engagement with a number wheel of a clearing rod tooth will be theoretically restricted to at most 36 when the digit 9 has been set up (or digit 1 if the clearing is effected in the opposite sense).

After the shaft has completed one revolution, and the clearing has been effected the clearing rod (or the shaft) has leapt back either when turning through the angle subtended between 0 and 9 with the effect of further reducing the angle available to the clearing rod for being turned into operative engagement with the wheels, or just before the zeros have attained their final positions whereby their proper alignment may be adversely affected.

In the known mechanism the cam governing the axial displacement of the shaft or the clearing rod must have a steep cam surface, and by that fact friction is increased and smaller dimension tolerances in the machined parts are necessitated. Those disadvantages will be acutely felt in such machines where the clearing operation shall be used in some cases for feeding back or transmitting a number calculated or set up in counting mechanism for example to the calculating rotor or to a storing register. Rather great forces will be needed to manipulate the keys and other control members of the machine on account of the steepness of said cam, and the ensuing Wear will be considerable.

With the object of eliminating completely the disadvantages recited above the invention among other things contemplates the provision of a much less steep shape of the governing cam which means that the portion of the clearing operation during which the clearing rod is moving axially may be extended over a much greater part of a revolution than the 36 afforded by known mechanism.

Instead of being released at the end of its travel to return suddenly to its rest position by the action of spring means, the clearing rod is controlled according to the invention in a positive manner during its whole cycle of motion. The rotation of the clearing rod may also be continued some angular distance beyond the actual zero position for the wheels actuated by the rod, that being of particular importance if there is play and lost motion between the gears to make up for when clearing calculating wheels, or when transfer or feed-back of the counting mechanism values to another counting mechanism or a storing register shall be effected. The rotation of the clearing rod thus may be arrested in a predetermined position, whereafter it is reversed, and is returned positively to its original position.

The improved mechanism according to the invention thus will operate much more accurately than known mechanism, and it will work reliably for both clearing and transfer operations Without the need of machining the participating elements to particularly close tolerances.

A mechanism for clearing the counting mechanism in calculating machines, particularly pin-wheel machines, whereof all number or calculating wheels are disposed on a common shaft, and a clearing rod accommodated in a longitudinal groove in the shaft engages at one end cam means provided on a toothed wheel journalled on the shaft and engaging a drive member such as a toothed segment which is actuated when clearing shall be effected, and further engages a fixed guide member secured to the stationary frame of the machine, said clearing rod being provided with teeth which are brought into engagement with corresponding members (teeth, notches, etc.) in the number wheels or calculating wheels to be cleared, said clearing rod returning to its inactive position after finished clearing, according to the present invention is particularly characterized by the fact that the clearing rod and the shaft are prevented from rotating during the first phase of the clearing rotation of said toothed wheel by the fixed guide member, the clearing rod being moved purely axially to accomplish an engagement with the number or calculating wheels by the action of the toothed wheel cam means engaging two lug members thereon, whereas upon continued rotation of the toothed wheel such engagement of the shaft and the clearing rod with the fixed guide member preventing the rotation of the former will cease so as to permit the shaft and the clearing rod to be carried along in rotation by the toothed wheel and consequently to turn the number or calculating wheels into their zero positions, the toothed wheel being thereafter returned to its original inactive position.

An embodiment of the invention will now be described by way of example with reference to the appended drawings, in which:

FIG. 1 is a sectional elevation of clearing mechanism according to the invention, and with the different parts taking up their inactive positions, a certain calculating wheel having assumed the angular position corresponding to the number 3.

FIGS. 2, 3 and 4 are cross sections along the lines A2A2, B3B3 and C4-C4 in FIG. 1, respectively.

FIG. 5 is a sectional elevation similar to FIG. 1 after clearing has been effected, but the parts have not yet returned to their inactive positions.

FIGS. 6, 7 and 8 are cross sections along the lines D6-D6, E7-E7 and F8l 8 in FIG. 5, respectively.

FIG. 9 is a perspective view of the mechanism illustrated in FIGS. 1 to 8 with certain elements broken away and others left out for an unobstructed view.

The calculating machine for which the illustrated clearing mechanism is particularly intended is provided with calculating mechanism comprising a product register and a quotient register which form two separate units. Each register is cleared separately upon turning a toothed segment 7 at the left side of the product register, and a similar segment to the right for the quotient register, respectively. The quotient register has not been specifically illustrated in the drawings, but resembles the product register closely as far as the present invention is concerned, and accordingly only one clearing mechanism need be described.

The tooth segment 7 engages a tooth wheel 3 which is rotatably disposed on a shaft 1 which supports the wheels the clearing of which is the purpose of the present invention. The toothed wheel 3 is prevented from axial displacement by a flange 3:! formed integrally therewith, and engaging a corresponding slot in the stationary structure 6. The shaft 1 may rotate, but is secured longitudinally with regard to the stationary structure 8 by a slotand-flange connection at its right end. A longitudinal groove is milled in the shaft, and a clearing rod 2 is fitted into said groove and is displaceable longitudinally thereof.

The tooth wheel 3 is formed with a hub having two cam portions 3a and 3b shaped thereon which engage two teeth 2c and 2d, respectively, formed integrally with the clearing rod, in such a manner that when the tooth wheel 3 is rotated clockwise, see FIG. 2, the cam portion 3b actuates the tooth 2a to move, and consequently the complete clearing rod is pushed to the right as long as the rod is prevented from rotating. Upon the rotation of the tooth wheel 3 in the opposite sense the tooth 2c is actuated by the other cam portion 3a to pull the clearing rod 2 to the left.

A fixed discor plate-shaped guide member 4 is secured to the stationary structure, and a bore therein is passed through by shaft ll. The guide member 4 is formed with a groove 4a in the wall of the bore which accommodates a tooth 2a, formed integrally with the clearing rod. The length of the groove 4a is such that the tooth 2a remains guided by the groove until the last portion of the axial displacement of the clearing rod, and the latter is prevented from rotating until the engagement between the groove 4a and the tooth 2a has ceased. Upon the longitudinal displacement to the right of the clearing rod 2 its teeth 2b, one for each calculating wheel (only one wheel illustrated) have moved into the hollow hub portions of the corresponding calculating wheels 5. When actuated by the cam portion 3b the clearing rod has attained its extreme right end position, the tooth 2a has become free from the groove 40, see FIG. 5. At the same time the tooth 2d which has followed the whole length of the cam portion 3b will strike against an end face Be on the cam portion 3b, and that end face 30 will serve subsequently to transmit the rotation to clearing rod 2 and shaft 1 at the end of the clearing operation.

During the said rotation the teeth 2b engage lugs 5a within the hollow hubs of the calculating wheels 5, see FIG. 4, and turn the latter to zero position as illustrated in FIG. 8. As illustrated in FIG. 7 the angular movement of the shaft is limited by the tooth 2a of the clearing rod 2 striking a fixed lug 4b (FIG. 3) in the guide memher 4.

After the clearing operation has thus been effected the mechanism will return to the rest position by the action of a spring 9 the tension of which is increased when the segment 7 is turned as for a clearing operation. During the first portion of the return movement of drive member 3, the shaft 1 will rotate in the reverse direction. However, when tooth 2a engages tooth 4b the shaft 1 is prevented from rotating and during the last portion of the return movement of drive member 3 the clearing rod is moved to the left due to engagement of lug 2c on clearing rod 2 with the cam face 3a.

To facilitate the return movement of the clearing rod the fixed guide member 4 is provided with a slightly helical guide face 40 against which tooth 2a bears. Thus as shaft 1 rotates in the forward direction, the clearing rod 2 will move a small distance to the right so that teeth 2b move towards the calculating wheels 5. Due to this action the friction between the tooth 2a and the guide face 4c is reduced to a minimum at the return movement of the clearing rod.

The embodiment described above and illustrated in the appended drawings has been chosen only by way of example, and the invention may be modified in many respects within the scope of the appended claims by those skilled in the art.

What I claim is:

1. In a mechanism for clearing the counting wheels of calculating machines particularly of the pinwheel type, in combination, a common shaft on which the counting wheels are disposed a clearing rod mounted for reciprocation in a longitudinal groove of the common shaft, said rod having a plurality of teeth corresponding to the number of counting wheels of the machine, said teeth being engageable with the counting wheels when clearing is to be effected, a toothed wheel rotatably mounted on said common shaft, a drive member engaging said toothed wheel and actuated when clearing is to be effected, a pair of cam means on said toothed wheel, a pair of lugs on said clearing rod, one of said lugs engaging one of said cam means to cause said clearing rod to reciprocate in said groove as said toothed wheel is rotated in one direction, a fixed guide mounted adjacent said clearing rod, a projection on said rod engaging said guide to prevent rotation of said common shaft during a first portion of rotation of said toothed wheel in a clearing direction during which said clearing rod moves axially into position to cause engagement of the teeth thereof with corresponding counting wheels, said guide having a limited length to free said common shaft and said clearing rod for rotation by said toothed wheel during a second portion of rotation of said toothed wheel to thereby rotate the counting wheels to a cleared position, means for returning said toothed wheel to its initial position and means comprising a fixed stop for engaging said clearing rod projection and arresting the return rotation of said shaft when said return rotation has progressed so that said projection on said clearing rod is in alignment with said guide whereby the other of said pair of cam means cooperates with the other of said pair of lugs to cause said clearing rod to return to its initial axial position.

2. In a mechanism for clearing the counting wheels of calculating machines particularly of the pinwheel type, in combination, a common shaft on which the counting wheels are disposed, a clearing rod mounted for reciprocation in a longitudinal groove of the common shaft, said rod having a plurality of teeth corresponding to the number of counting wheels of the machine, said teeth being engageable with the counting wheels when clearing is to be effected, a toothed wheel rotatably mounted on said common shaft, a drive member engaging said toothed wheel and actuated when clearing is to be effected, a pair of cam means on said toothed wheel, a pair of lugs on said clearing rod, one of said lugs engaging one of said cam means to cause said clearing rod to reciprocate in said groove as said toothed wheel is rotated, a fixed guide mounted adjacent said clearing rod, a projection on said rod engaging said guide to prevent rotation of the common shaft during a first portion of rotation of said toothed wheel in a clearing direction during which said clearing rod moves axially into position to cause engagement of the teeth thereof with corresponding counting wheels, said guide having a limited length to free the common shaft and said clearing rod for rotation, said cam means terminating in an abutment to drive the corresponding lug and the common shaft during a second portion of rotation of said toothed wheel to thereby rotate the counting wheels to a cleared position, means for returning said toothed wheel to its initial position and means comprising a fixed stop for engaging said clearing rod projection and arresting the return rotation of said shaft when said return rotation has progressed so that said projection on said clearing rod is in alignment with said guide whereby the other of said pair of cam means cooperates with the other of said pair of lugs to cause said clearing rod to return to its initial axial position,

3. A device in accordance with claim 1 wherein said fixed guide member is shaped as a disk having a notch therein corresponding to said clearing rod projection, said notch preventing the rotation of the shaft and the clearing rod during the axial displacement of the latter and permitting that rotation thereafter and wherein a lug is provided on said disk, said lug being in the path of said clearing rod projection and limiting the rotation of said common shaft.

4. A device in accordance with claim 2 wherein said fixed guide member is shaped as a disk having a notch therein corresponding to said clearing rod projection, said notch preventing the rotation of the shaft and the clearing rod during the axial displacement of the latter and permitting that rotation thereafter and wherein a lug is provided on said disk, said lug being in the path of said clearing rod projection and limiting the rotation of said common shaft.

5. A device in accordance with claim 3 wherein said fixed guide disk has a slightly helical guide face formed thereon, said guide face cooperating with said clearing rod projection to move said clearing rod tooth a small distance axially toward the counting mechanism wheels to reduce friction between said clearing rod projection and said guide face during return movement of the drive member and the common shaft.

6. A device in accordance with claim 4 wherein said fixed guide disk has a slightly helical guide face formed thereon, said guide face cooperating with said clearing rod projection to move said clearing rod tooth a small distance axially toward the countin mechanism Wheels to reduce friction between said clearing rod projection and said guide face during return movement of the drive member and the common shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,358,058 Chase et a1 Nov. 9, 1920 1,413,713 Enders Apr. 25, 1922 1,654,441 Wernecke Dec. 27, 1927 

